jnr.ffi.util.Annotations Maven / Gradle / Ivy
/*
* Copyright (C) 2012 Wayne Meissner
*
* This file is part of the JNR project.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jnr.ffi.util;
import java.lang.annotation.Annotation;
import java.util.*;
/**
* Utilities for collections of annotations
*/
@SuppressWarnings({"unchecked" ,"rawtypes" })
public final class Annotations {
public static final Collection EMPTY_ANNOTATIONS = Collections.emptyList();
private Annotations() {}
public static Collection sortedAnnotationCollection(Annotation[] annotations) {
if (annotations.length > 1) {
return sortedAnnotationCollection(Arrays.asList(annotations));
} else if (annotations.length > 0) {
return Collections.singletonList(annotations[0]);
} else {
return Collections.emptyList();
}
}
public static Collection sortedAnnotationCollection(Collection annotations) {
// If already sorted, or empty, or only one element, no need to sort again
if (annotations.size() < 2 || (annotations instanceof SortedSet && ((SortedSet) annotations).comparator() instanceof AnnotationNameComparator)) {
return annotations;
}
SortedSet sorted = new TreeSet(AnnotationNameComparator.getInstance());
sorted.addAll(annotations);
return Collections.unmodifiableSortedSet(sorted);
}
public static final Collection mergeAnnotations(Collection a, Collection b) {
if (a.isEmpty() && b.isEmpty()) {
return EMPTY_ANNOTATIONS;
} else if (!a.isEmpty() && b.isEmpty()) {
return a;
} else if (a.isEmpty() && !b.isEmpty()) {
return b;
} else {
List all = new ArrayList(a);
all.addAll(b);
return sortedAnnotationCollection(all);
}
}
public static final Collection mergeAnnotations(Collection... collections) {
int totalLength = 0;
for (Collection c : collections) {
totalLength += c.size();
}
List all = new ArrayList(totalLength);
for (Collection c : collections) {
all.addAll(c);
}
return sortedAnnotationCollection(all);
}
}